* A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
* Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
* A [bug in OpenKeychain](https://github.com/open-keychain/open-keychain/issues/2688) causes invalid PGP signatures when using a hardware token.